Continuous distillation of crude petroleum oils



oct. 11.1924 Y F. M. ROGERS ET AL CONTINUOUS DIS'ILLATION OF CRUDEPETROLEUM OILS .NNN

Jan. 25, 1927'.

Patented Jan. 25, 1927.

UNITE STATES FRANCIS M. ROGERS, 0F WI-IITING', INDIANA, AND ROBERT E.WILSON, OF CHICAGO, ILLINOIS, ASSIGNORS TO STANDARD OIL COIVIYANY, OFIVI-IITING, INDIANA, AND CHICAGO, ILLINOIS, A CORPORATION OF INDIANA.

CONTINUOUS DISTILLATION OF CRUDE PETROLEUM OILS.

Application lerl October 11, 1924. Serial No. 743,001.

The present invention relatesto `improvements in the continuousdistillation of crude petroleum oils, and will be fully understood fromthe following description, illustrated by the accompanying drawings, inwhich the figure shows diagrammatically apparatus suitable for carryingthe invention into effeet.

Referring to the drawing, the numeral 5 indicates the end stills of abattery or series ot continuous stills, such as are ordinarily employedin the continuous distillation of 'petroleum oils with fire and steam.From the last ot the battery of continuous stills the heated residuumIis discharged or pumped into the coil 7 mounted in a suitable setting8, the coil of the usual cleanable form, and its setting being showndiagrammatically in the drawing. Steam or other inert gas may beintroduced into the coil through the valve line 9, communicating withthe inlet of the coil. From the coil oil passes through a line 10,preferably of greater cross-sectional area than the coil 7, and into avaporizing chamber or drum 11. The vaporizing drum 11 may be providedwith a suitable device or separator 12 for removing entrained liquidfrom outgoingv vapors. The separator 12 communicates with the vapor pipe13 leading to the condenser coil 14, from which condensate passes into areceiving drum 15, in

which a separation of oil and water maytake place. Oil may be withdrawnthrough the valved discharge line 16 and water may be withdrawn throughthe discharge line 17. From the vapor space of the .receiving drum 15 aline 18 communicates With the vacuum pump 19.

Residues are removed -from the vaporizing drum 11 through the valvedline 20, which communicates with the intake ot the hot oil or surge pump21. In carryn out the invention, a crude or equivalent oi such asreduced crude oil, is

reduced with fire and steam to a suitable bottom, say up to 20% andpreferably 10 to 15% of the crude, in the battery of continuous stillsby meansA of lire and steam. The temperature prevailing in the last ofthe stills 5 may be from 600 to 6500 F. The residue passes through thepipe 6 into and through the heated coil 7, steam being added in thequantity desired to the steam inlet pipe 9. The proportion of steamemployed varies with different oils and with the character of overheaddistillate desired. In general, from 1 to 10 pounds of steam per gallonof distillate are employed, but this may be .varied within wide limits,depending on the vacuum employed, the nature of the crude and productdesired, etc. In passing through the coil 7 the oil is brought to ahigher temperature, say 700 to 800O F. and preferably 'from 720 to 7 500F. From the coil 7 the oil and steam are drawn into the enlarged pipe10, which is preferably of considerable length, so as to permit theattainment of substantial equilibrium between vapors and liquid. Theheated oil, oil vapors and steam then enter the separating drum 11, inwhich separation of vapors from oil residue takes place. The vapors passout through the entrainment separator 12 and vapor line 13, theentrainrnent separator 12 removing entrainment particles of oil andconsequently discoloration or other impairment of the distillate. Theseparated vapors then pass into the condenser 111, from which condensateflows to the receiver 15. In the receiver, condensed water and oil maysuitably be separated.

The vapor space of the receiving drum 15 is connected with the vacuumpump 19, by which a suitable .vacuum is maintained in the separatingdrum 11. An absolute vpressure of from1 to 3 inches of mercury or up to4t inches may suitably be maintained in the separating drum by thevacuum pump.

The residue in the separating drum, While still in liquid state, isdrawn out through the valved line 20 by the .pump 21. This residue mayvary from 20 to 50% on the residuum discharged from' the last of the.continuous stills, or from 2 to 6% on the original crude in the case ot'mid-continent crude. With other crudes, these proportions may vary, in

the original crude and had' a melting point a stock for @racking intogasoline, if so de-V sired. l

7e claim: f' 1. The method of continuous distillation of crude petroleumoils which comprisesV reducing the oil to a very heavy bottom bysubjecting the oil to the action of heatand steam, passing said veryheavy bottom, acb companied by' steam, through `a confined passage in aheat-ing zone at a temperature y sufiicient to bring the oil toatemperature of 70() to 800 Fl, introducing the heated oil and steam4into al chamber' in which separation of vapors and liquids takes place,separately removing the vapors and liquids therefrom, and maintainingWithin said chamber absolute pressure of. less than 4t inches ofmercury."

2. The method of reducing' crude petroleum oils comprising subjecting apetroleum oil to distillation with fire and open steam to bring said oiltoa very heavy residue amounting to not over" 20% on-thee origina-lcrude, lpassing sai-1d- -res1due, accompanied by steam, through aconfined pas- 3. The `method ot reducing crude petroi leum oilscomprising subjecting' mid-con= tinent petroleum oil to distillationwith fire and 4Steam to bring said oil to va pitchbot-= tom o- 1() to15% of the original crude, passing said bottom, accompanied by steam,through a confined passage in a zone heated 'to bring the temperature-ofthe oil tol/720 to 750 F., introducing the heated oil and steam into achamber iii-which an abselute pressure of 1 to '3 inches'of mercury' ismaintained, and removing vapors' and `unvaporized residue separately.therefrom FRANors Roor'mrs.y ROBERT WILsorr

